Mechanism for removing and transporting a group of sheets from the top of a supply stack



P. J. BARDY VING AND TRANSPORTING A GROUP OF 6 Sheets-Sheet l E yshim? April 2, 1963 MECHANISM FOR REMO SHEETS FROM THE TOP OF A SUPPLY STACK Filed Feb 13 1958 0 mxl lflq as? 1 v N? a 8 QRN @QN WQN Wm, .wMN M 0 1 N L mg O I fl MM 6 Sheets-Sheet 2 April 2, 1963 P. J. BARDY MECHANISM FOR REMOVING AND TRANSPORTING A GR SHEETS FROM THE TOP OF A SUPPLY STACK Eraniar PP ferJ Boroy zzwgfizz 5 hawk NM .91 smw Filed Feb. 13, 1958 Aprll 2, 1963 P. J. BARDY 3,083,963

MECHANISM FOR REMOVING AND TRANSPORTING A GROUP OF SHEETS FROM THE TOP OF A SUPPLY STACK Filed Feb. 1:, 1958 e Sheets-Sheet s L z-liar PP fer 7. Baroy A ril 2, 1963 my 3 083,963

P. J. BA MECHANISM FOR REMOVING AND TRANSPORTING A GROUP 0% SHEETS FROM THE TOP OF A SUPPLY STACK Filed Feb. 13, 1958 6 Sheets-Sheet 4 I 80 75' I my 70 7 EVE-liar Pe fer :Z' Bare y Biz- %M/ ZiU Apr 1963 P. J. BARDY 3,083,963

MECHANISM FOR REMOVING AND TRANSPORTING A GROUP OF SHEETS FROM THE TOP OF A SUPPLY STACK Filed Feb. 13, 1958 6 Sheets-Sheet 5 '1 Ban-far Pefer J Bardy Apn] 2, 1963 P. J. BARDY 3,083,963

MECHANISM FOR REMOVING AND TRANSPORTING A GROUP OF SHEETS FROM THE TOP OF A SUPPLY STA Flled Feb 13 1958 OK 6 Sheets-Sheet 6 United States Patent 3,033,963 MECHANESM FUR REMUVHNG AND TRANSPGET- ENG A GRQUP 0F SHEEld FRUM THE TSP 0F A SUPELY STACK Peter J. Bardy, Parlr Ridge, til, assignor to General grading Qorporation, Chicago, ill, a corporation of mots Filed Feb. ltd, N58, tier. No. 7l5,il29 tjlaims. (til. 271-43) The present invention relates to improvements in automatic machines for handling sheets of material and more particularly to an improved machine and method for automatically removing individual groups of sheets mm a stacked supply of collated sheets and transporting the groups to an operational station maintaining the sheets i the group in alignment for simultaneously performing an operation on all of the sheets of the group.

As an example of an operation which may be performed with a machine constructed and operated in accordance with the invention, a supply stack of paper may be accurately punched for receiving binding devices to bind the sheets into book form. Where the supply is too large to be punched in one operation, individual groups of sheets are removed from the top of the stack and are transported to a punching station, and thereafter discharged while being retained in alignment and in collated assembly. Groups of sheets are separated from the supply staclc by a separator elevating a central portion of the group to lift the group of sheets above the stack. The lower jaw of a gripping jaw assembly enters the gap between the group of sheets and the top of the remaining supply stack, and an upper jaw clamps downwardly to grip the sheets closely adjacent the separating mechanism and an advancing means carries the jaws forwardly along a substantially horizontal path to slide the group of sheets off the top of the stack while a hold-down member clamps the uppermost sheet to the top of the remaining stack to present a stable sliding surface for the group and retain the stack in alignment. A group of sheets is delivered along a horizontal path to a punching station where a disappearing stop moves upwardly to engage the advance edge of the group of sheets holding them in alignment during punching. After the group of sheets are punched, the gripping jaws release the sheets and they are advanced between continually rotating discharge rollers which carry the group of sheets further along the path and out of the machine. The mechanism proceeds to automatically operate to bring another group into the operating station.

An object of the present invention is to provide an improved automatic high-speed machine which will successively remove groups of sheets off the top of a supply stack and deliver the sheets in aligned relationship to a punching station or the like.

Another object of the invention is to provide an automatic machine for forming aligned punched holes in a large supply of sheets wherein the holes are formed by punching individual small groups of sheets.

Another object of the invention is to provide an automatic handling machine for stacks of sheets wherein the sheets may be punched and then be discharged in such a position that an automatic cover insertion or automatic binding machine is utilized. The sheets are retained in alignment and can be handled automatically.

Another object of the invention is to provide an improved sheet handling machine provided with improved devices for retaining the alignment of sheets during conveyance and during operation on the sheets.

Another object is to provide a sheet handling machine wherein the sheets will not be marred or damaged during 3,083,953 Patented Apr. 2, 1963 high-speed mechanical handling nor during operations on the sheets.

Another object is to provide a sheet handling machine which is easy to load and simple to maintain.

A further object of the invention is to provide a sheet handling machine with improved features adaptable to increased speed of operation and increased accuracy and reliability of operation.

(Ether objects and advantages will become more apparent with the disclosure of the invention and the teaching of the principles thereof, in the description and showing of the preferred embodiment in the specification, claims and drawings, in which:

FIGURE 1 is a plan view of the head end of the machine embodying the principles of the present invention;

FIGURE 2 is a vertical sectional line taken along line lI-ll of FIGURE 1, and illustrating the internal operating mechanism of the head end of the machine;

FIGURE 3 is a vertical sectional view taken along line Ell -Ill of FIGURE 2;

FIGURE 4 is a detailed sectional view taken along line lVlV of FIGURE 3;

FIGURE 5 is an enlarged detailed elevational view of the gripping jaws for gripping groups of sheets;

FIGURE 6 is a vertical sectional view taken along line VI-Vl of FIGURE 2;

FIGURE 7 is a side elevational view of the mechanism for elevating a supply stack of sheets;

FIGURE 8 is a plan View of the tail end of the machine;

FIGURE 9 is a vertical elevational view taken along line lXlX of FIGURE 8, and;

FEGURE 10 is a schematic elevational View showing the sheets being gripped.

As shown in the drawings:

The mechanism is shown and described as operable to advance individual stacks of sheets of paper to a punching machine, inasmuch as numerous advantages are achieved with the invention for this type of operation on the sheets. However, it will be understood that the invention may be adapted to use for other operations on sheets, and the mechanism disclosed and described may be embodied in other assemblies, using the natural advantages of the inventive features thereof, and the preferred embodiment is shown by way of illustration, and not by way of limitation.

As illustrated in FIGURES 1 and 8, which show the head and tail ends of the machine respectively, the mechanism has a surface plate it), which forms part of the framework and permits support of various operating elements of the machine. As illustrated in FIGURE 1, this plate has an opening 12, through which a supply stack 14 of sheets is elevated for purposes of removing groups of sheets from the top of the supply stack. The supply stack 14 is shown in FIGURE 7 as being elevated in step-bystep operation through the opening 12 during operation of the machine.

As may be best viewed in FIGURE 2, with individual elements also being shown in other figures, a group of sheets is lifted off the stack by operation of a separator 13. The separator is a downwardly extending arm pivotally supported on a cross-shaft 2d to depend downwardly. At its lower end, the separator has a separating finger 22 projecting toward the stack 14. In operation, the separator is pivoted forwardly, to the left, as shown in FlG- URE 2, to lift a group of sheets from the top of the stack. As will be noted in FIGURE 1, the separator finger 2-2 is pointed in shape so as to easily slip between the sheets and is located somewhat near the midpoint of the stack of sheets. Thus, as the separator finger 22 moves upwardly, the center portion of the group of sheets will be gripping jaw assembly 2d, as shown in EEG '1 ES 1 end 2, and as shown in detail in FTGURE 5. T1 assembly includes a ower gripping jaw 25, which is tapered so to easily slip into the gap between the elevated group sheets and the top sheet of the remainder of the stack. The lower surface of the lower gripping jaw 26 will always clear the top of the stack, and a clearance of the order of ,6, of an inch has pro :1 satisfactory.

The grippin" jaws 24 are carried on a sheet advancing assembly 28, rich is operative to move forwardly toward the tail end of the machine to carry the sheets along a substantially horizontal path to an operating station where they are punched.

An upper jaw is pivotally mounted on the forward end of a sheet advancing bar 32 so as to be movable between a release position and a grpping position. In the gripping position, the upper jaw it) is brought downwardly toward the lower jaw 26 to pinch or clamp the group of sheets therebetween.

The gripping jaws move forward and grip the sheets to slide them along the path to the punching sta on. To provide a stable sliding surface, and to main in the upper sheet of the remaining stack in position, a holddown member 34 clamps the uppermost sheet to the stack. The hold-down member is shaped of an arm supported on a pivot pin 3.6 having a projection with a downwardly facing surface which is moved over the top of the stack.

With reference to Figure 9, the operating or punching station is shown provided with a punch It will be seen from FIGURE 9 that as the stack of sheets 1 is elevated through the opening 12, the groups which are slid off the top will be slid onto the top surface of the plate 10, and moved between guides 4-2 toward the punching station shown generally at 44.

At the punching station, a disappearing stop member 46 is brought up into the path of travel of the sheets to engage the leading end and accurately po Ion the sheets as well as aligning the placement of the individual sheets of the group.

After the sheets have been punched, the disappearing stop 46 drops downwardly and the sheets are carried forwardly into the bite of the discharge rollers dB and These rollers operate continuously and deliver the punched sheets further along the path for binding or reassembly.

The operating mechanism for operating the aforedescribed elements will be described in sections in accordance with the elements operated.

The Separator The separator 18 is pivotally suspended on a shaft 2 3 for pivotal rocking movement. Each forward pivotal movement of the projecting finger Z2 lifts the center of a group of sheets.

To pivot the separator and pivot th supporting shaft 29, a crank arm 52 is connected to the shaft 29 and is pivoted by connecting rod 52 extending toward the head end of the machine. The end of the rod 52 is connected to a rocker arm 54-, having a cam follower 56 at the opposite end. The rocker arm is pivoted on a bracket 58, supported below the surface plate ill. A tension spring 59 is connected between the bracket 53 and the rod 52 to hold the follower 56 in engagement with its cam 60. This relationship is best shown in FIGURE 2, and is also illustrated in FIGURE 3.

The cam 60 for operating the separator 13 which lifts the group of sheets, is mounted on a main drive shaft 62, which is suitably driven at a constant speed by mechanism, not shown. Preferably, the main drive shaft 62 is operated through a variable speed control so that the speed of the machine may be regulated.

Supply Stack Elevating Mechanism The supply stack rests on an elevating base 76, as shown in FEGUILES 7 and 9, and is elevated step-bystep to maintain the top of the stack at the proper level for removing each succeeding group or sheaf of sheets therefrom.

The base or platform 7% is illustrated as suspended on cables 72. and '74 which lead upwardly to pass around winch drums 76 and 73. The drums are mounted on shafts 39 an 82, respectively, and the shafts are geared together so as to rotate simultaneously and maintain the base I -L a level position.

The base is elevated in a step-by-step motion, and is operated in timed relationship to the rest of the machine. The shafts 3t) and 32 are geared together by connecting shafts, not shown, and shaft is intermittently rotated by a pawl and ratchet mechanism.

Carried on the shaft it is a ratchet gear 84 provided with ratchet teeth 36. The teeth are engaged by a reciprocating pawl 83, which is driven in reciprocation from a cam, not shown. The cam is driven by a shaft geared to the main drive shaft 62 to operate in synchronism with the rest of the machine, and this mechanism is not shown, since its operation will be apparent to those skilled in the art. The ratchet gear 84 and the shaft will be held witn cach advance by a pivotal dog 90, which engages the teeth of the ratchet to hold it. In this manner, the separator 18, each time it moves forward, will lift a new group of sheets off the top of the stack, inasmuch as the stack will be elevated the proper amount for each operation. The amount of advancement can be controlled by the design of the stack elevating mechanism, and in the present instance, as many sheets as can be conveniently handled by the punch, are advanced with each successive cycle of the machine.

The Gripping and Advancing Mechanism The gripping jaws 24 will grip the group of sheets and the advancing assembly 28 will carry the sheets forwardly sliding them off the stack toward the punching station As illustrated in FIGURES 2 and 5, the lower gripping jaw 26 has a curved upper surface 92 to somewhat conform to the curvature of the group of sheets as they are lifted off the top of the stack.

The upper gripping jaw 30 has a curved lower surface 94 which is concave in nature, and matches the convex curvature of the surface 2.

The upper gripping jaw 3t) carries a paid of soft resilient material 95 which aids in gripping the sheaf of sheets.

It will be noted that the sheets are gripped closely adjacent to the point where they are lifted by the separator 13 so that what sliding occurs between the sheets when the central portion is lifted, will have little effect in displacing the individual sheets. Furthermore, this makes it necessary to lift only one section of the sheets, and the edges can remain supported by the stack.

The upper gripping jaw 30 is carried on the end of one arm of a bell crank member 93, which is pivoted at the forward end of the slide or advancing member 32.

The slide, as may be viewed in FIGURES l, 2, 3 and 6, is illustrated as formed of a fiat piece of sheet metal shaped to have a raised center portion with outwardly extending sides 162 and 104. These sides are guided for sliding movement of the slide by ways or gibs 186 and 198, which are secured to the top plate 19, such as by bolts.

The advancing slide 32 is moved in reciprocation along the ways 1% and 1% by a rack and pinion assembly with a rack 110 being secured underneath the raised cen tral portion 100 of the slide 32;, such as by bolts 1 12. The rack 110 is driven by a pinion 114, FIGURE 6, which is mounted on a cross shaft 116. The pinion 114 is pinned to the cross shaft at .118 to be driven thereby.

As illustrated in FIGURES 2 and 6, the cross shaft 116 is driven by a second smaller pinion 120, also secured to the cross shaft at 122. The pinion is driven by a horizontally sliding rack member 124. The rack member 124 is held in contact with the pinion 120 by a supporting bearing 126 secured at the lower end of a bracket 128, suspended from the upper plate ll). The downwardly depending bracket 128 cooperates with another downwardly depending bracket 13!) for supporting the cross shaft 116 which carries the two pinions 1-14 and 12d. The bracket 13% is also supported from the top plate Ill.

With reference to FIGURE 2, the rack and pinion assemblies for driving the advancing slide 32 forwardly are driven by the lower rack 124. This rack is connected to an extension rod 132. which is slidably supported in a downwardly depending bracket 134 secured at its upper end to the top plate It). The extension rod 132 carries a follower 136 which rides in a closed cam track on the side face of a earn 138. Cam 138 is mounted to be driven in rotation with the main drive shaft 6-2. The details of the cam 138 and follower 136 are illustrated in the sectional view of FIGURE 4. As shown therein, the rack 124 is connected to the extension rod 132 by intermediate connector members 140 and 125. The rack 124 is bolted to connector 125. Connector 141) is provided with axial holes open on each end to receive reduced ends 142 and 144 of the connector 125 and the extension rod 132, respectively. Reduced ends are secured by cross pins 146 and 148 which extend through holes in the connector 1-45 and holes through the reduced ends 142 and 144. The cam follower 136 extends through an opening in the connector 14%, and is secured therein by having a threaded end which receives securing nuts 150.

The main drive shaft '62 is rotatably supported on downwardly extending bearing brackets 152 and 154, which are secured at their upper ends beneath the top plate 10, as illustrated in FIGURE 3.

The clamping jaws 24 are automatically operated to grip the paper as the advancing slide 32 is moved forwardly along the advancing path. The upper gripping jaw 30 is brought down against the lower gripping jaw 26, by pivotal movement of the bell crank 98. The crank is pivoted by a connecting rod 156 which is connected to the upper arm of the bell crank, and which is connected at its other end to an arm 158 connected to a cam 169. The arm is the lower arm of a bell crank 152 with an upper arm 164 connected to a coil tension spring 166. The tension spring is suitably secured to the frame of the machine so as to apply a constant tension to the bell crank 1 62 to tend to rotate it in a clockwise direction, as shown in FIGURE 2. This will tend to draw the connecting rod 156 to the right, and pivot the upper jaw so to an open position.

To close the upper jaw, the cam follower 160 rides up along the top of a cam track 168, which is located along side of the path of travel of the slide 32. The cam follower 16() is pivotally mounted on top of the slide 32 so as to be carried along therewith. When the follower 166) rides on top of the cam track 168, the connecting rod 156 will be pushed forwardly to close the upper jaw 39- against the lower jaw 26. The connecting rod 156 is connected to the bell crank 93 by a connector member 17%;" which has a hollow axial bore to receive the end of the connecting rod 156, and the rod is pinned thereto by a pin 172, extending through slots 174 in the side of the connector member. A compression spring 176 biases the pin 172, to one end of the slot 174 by pressing between the connector member 179 and a collar 178 on the connecting rod 156. This pin 172 and slot 174- will permit compression of the spring 176, in order that the group of papers between the jaws so and 26 will be resiliently pinched or gripped to obtain firm gripping without damaging the papers.

The group of sheets will continue to be gripped in forward movement of the slide 32 until the cam follower 1-60 is kicked laterally off of the cam track 168. This is accomplished by a release cam 18% which is positioned at the other side of the slide 32. This release cam has a leading face 19%, angled with respect to the path of the slide, so as to engage the far end of a pivotal support pin 192 for the earn 166 and the bell crank 162.

The pivotal support pin B2. extends laterally through a support bracket 1% which is mounted on top of the slide 32. The pin 192 is of a sufficient length to permit it to slide laterally, as shown in detail in FIGURE 1. The support pin 192 has an enlarged end 1% which serves as a follower and which engages the inclined face Hit of the release cam 188. The enlarged end 1% also holds a coil compression spring 2% on the pin, and this spring urges the pin 192 to a position where the follower 16% will he in alignment with the cam track 168.

Thus, as the slide 32 moves forwardly along its path, the follower 161} will ride on top of the track 163, but will be kicked olf the track when it reaches the position of the cam 138. With the return movement of the slide 32, the follower 16d will ride along side of the cam track 168, in which position the gripping jaws 24 will be open. At the end of the return path of travel of the slide 32, the follower 164} will pass the beginning end 202 of the cam track 163, and will be snapped back into alignment with the track by the spring 2% for a succeeding forward travel, whereupon the jaws will again grip a new group of sheets.

H old-Down Device the gap when a group of sheets are lifted to hold down the uppermost sheet of the remaining stack.

The arm 34- is pivoted on a pin 36, which is supported on a bracket 2%, supported beneath the top plate 14%. The hold-down arm 34 is pivoted at a midpoint with the lower end of the arm being connected to a connecting operating rod 206. The operating rod 2% moves toward the head end of the machine to pivot the hold-down arm 34 forwardly at its upper end, and the rod 266 is connected to the arm 34 by a connecting member 2%.. The connecting member 2&8 extends rearwardly with a downwardly depending flange 219, which has a central opening to receive the rod 296. This flange provides a stop for a compression spring 212, which also abuts a collar 214 on the end of the rod. Thus, when the'rod pulls toward the head end of the machine, the spring 212 can compress to resiliently and firmly cause the hold-down arm to grip the uppermost sheet of paper.

The other end of the operating rod 2% is'connected to the upper arm of a bell crank 216. The lower arm of the'bell crank has a follower 218, which rides on the surface of the cam 229 shown in FIGURE 3. The cam 220 is also mounted on the main drive shaft 62 and rotates therewith in timed relationship with the rest of the machine.

To holdthecam follower 218 in engagement with the cam 220, the bell crank 2.16 is provided with a rearwardly extending arm 222, as shown in FIGURE 2. Connected to arm 222 is a tension spring 224, FIGURE 3, which is anchored at its upper end by a pin 226, secured to the bracket 53.

Disappearing Stop stack, and has an even leading forward surface 228. The bar is carried at its ends on parallel links 23%) and 232 on one end, and 234, 234 at the other end, as shown in F16- URE 8. The links 239 and 232 are supported on a downwardly extending bracket 23 secured beneath the top plate iii. The links 23 i, 234 are secured to a similar plate on the other side of the machine, and assembly is shown generally by the hidden lines of FZGURE 8.

The parallel links will serve to hold the disappearing stop bar as in a vertical position throughout its t -vel and will move it between a recessed inoperative pa When the links are dropped downwardly and an operative position, as shown in 9, in a generally arcuate path. The bar is moved into operative position toward the sheets, so as to engage them from aendwise direction.

For operating the bar and the links, a pin projects from the end of the bar, as shown in FIGURE 9, between the point of connection of the two links 233 and 7.32. Since the bar is constructed the same on each side of the machine, only the end shown in full line in FIGURE 9 need be described in detail, and the opposite end, which is in the location shown in FIGURE 8, will be the same. This pin 23% is cradled between the projections of the bifurcated end of the lower arm of a bell crank 242. This bell crank is supported on a pin on a bracket 2%, supported beneath the top plate it). An upper arm of the bell crank is secured to an operating rod 25%, which leads forwardly to the front end of the machine, and which is shown in FEGURES l and 2.

The forward end of the rod 250 is connected to a crank arm 252 on a cross shaft 254. This shaft 254 carries a rocker arm 256 at its other end, and is suitably supported for pivotal movement beneath the top plate It).

The rocker arm 256 has a cam follower end 258 which engages a cam ring 260 that is bolted concentric to the side of the pinion 114, as shown in FIGURE 6. This is the pinion that drives the advancing slide forwardly. The cam arrangement 26% is secured to the face of the pinion 114, such as by bolts 262. As shown in FIGURE 2, the follower 258 is held in engagement with the cam ring by a tension spring 264 connected between the lower end of the arm 256 and a bracket 266 extending downwardly from beneath the top plate It).

Thus, the disappearing stop 46 will be operated in synchronism with the advancing slide 32. After the sheets are brought into the punching station 44 and punched, the disappearing stop 46 drops downwardly out of the path of travel, and the slide carries the sheets forwardly to the discharge rollers 48 and 59.

The Discharge Rollers The discharge rollers are driven in constant rotation and may be geared to each other to be rotated together. The upper rollers 48 and 49 are supported on a shaft 268, which is supported in bearings 27% and 272, as illustrated in FIGURES 8 and 9. The rollers 50 are positioned opposite rollers 48 and 49. The lower rollers 50, are carried on a shaft 274, which is supported in brackets 276, 276. The shafts may be connected together such as by a gear 278 at the end of the shaft 268 meshing with another gear, not shown, mounted on the end of the lower shaft 274.

The lower shaft carries a gear 280 which is driven by a gear 232, secured on a shaft 284. The shaft 284 is suitably driven, such as by carrying a pulley or sprocket to be driven by a belt or chain linked back to the main drive shaft 62 for driving the rollers continually with the rest of the machine.

An upper guide plate 286 is provided, having forwardly projecting edges 2&8 and 296 to keep the group of sheets from buckling after they are pushed forwardly along the path from the punching station. When the punching is finished, the slide 32 will begin to move forwardly to push the group of papers toward the discharge rollers. At this point the jaws 24 will open and the papers will be maintained in alignment by edge-aligning face 292, FIG- URE 2, which is located at the forward end of the slide 32. The edge-aligning face 292 pushes the group of sheets forwardly between the rollers, and the sheets are then carried out of the machine to tbe bound, assembled, or receive covers. The edge-aligning face 292 also function during the time the papers are being gripped to aid in maintaining them in alignment, and provides an opposing surface for the disappearing stop to insure the proper location of the group of sheets for engagement by the punch 46.

Although the operation will be understood from the description of the details of the individual parts, a brief summary of operation may be in order. The supply of sheets in collated relationship is stacked on a support 70, as shown in FIGURES 7 and 9. The support is indexed upwardly step by step each time a group of sheets is slid off the top of the stack 14. As shown in FIGURE 2, a group of sheets is first separated by a separator 18 pivotally turning in a clockwise direction, in order that the forwardly extending finger 22 may elevate a group and form a gap. A lower gripping aw 26 enters the gap by forward movement of a carrying slide 32, and an upper gripping 24 descends toward the lower gripping jaw 25 to pinch the sheets therebetween. As the slide 32 moves forwardly to slide the group of sheets off the top, a hold-down arm 34 pivots forwardly so that its upper projecting end 33 may hold the uppermost sheet against the remaining stack. The sheets are slid forwardly to a punching station 44, as shown in FIGURE 9, whereupon a punch 4% descends to punch the assembled sheets. A disappearing stop bar 46, in the meantime, has moved up into the path to engage the leading edge of the sheets, preventing them from being carried forward by inertia, and urging their alignment. After the punching has been completed, the slide 32 again moves forwardly whereupon the jaws 24 move open to release the sheets, and an edge-aligning face 92. pushes them forwardly between upper rollers 48 and 49, and lower rollers 50, 50 which operate continuously. These rollers discharge the punched sheets from the machine, retaining them in their collated relationship. The disappearing stop 46 has, of course, dropped down out of the path of the sheets to permit them to be moved forwardly along the path.

Thus, it will be seen that I have provided an improved machine which meets the objectives and advantages hereinbefore set forth, and operates in accordance with the methods taught herein. The machine is susceptible of high-speed operation, and will retain the individual sheets of the groups in their aligned position for accurate punching, or for other operations which may be performed on a group. in this manner, a succession of the same operations can be performed on an entire supply stack of sheets, and the sheets maintained in their collated relationship.

The machine is automatic in operation, and is driven from a single main drive shaft. The various operating elements are operated in timed relationship, and cooperate to simply and rapidly, successively remove groups of sheets from the top of a supply stack. The sheets are firmly gripped, and yet are gripped without the chance of incurring damage thereto, such as wrinkling or tearing. The stack of sheets forms the support for sliding the group off the top, and individual groups are separated by being elevated at their center location for only a small distance. Thus, the entire operation is performed by moving the sheets a minimum distance which reduces the velocity of movement necessary and enables a higher overall output of the machine. The mechanism for performing the individual operation is well coordinated, and operates with a minimum of velocity change or movement, so as to be capable of a long operating life and continued operation without adjustment.

I have, in the drawings and specification, presented a detailed disclosure of the preferred embodiments of my invention, and it is to be understood that I do not intend to limit the invention to the specific forms disclosed, but intend to cover all modifications, changes and alternative constructions and methods falling within the scope of the principles taught by my invention.

I claim as my invention:

1. A mechanism for removing a sheaf of sheets from a supply stack and advancing the sheaf in aligned relationship comprising a device for separating a sheaf of sheets from the top of a supply stack by slightly elevating the center of the sheaf with the edges remaining in contact with the stack, gripping jaws for moving against opposing surfaces of said sheaf at said elevated center, the upper of said jaws having a soft resilient surface and the lower of said jaws having an arcuate face curving to conform to the sheaf of sheets draping downwardly at the edges, means for moving the jaws together to gripping engagement with said sheaf, and advancing means carrying said jaws horizontally for sliding the sheaf off of the top of the stack.

2. A mechanism for advancing a group of collated sheets from a stack thereof comprising a separator for elevating slightly the center portion of one side of a group of sheets from a supply stack, a pair of gripping jaws adapted to be moved into gripping engagement with the center of said group of sheets, an advancing means movable along a horizontal path and carrying said gripping jaws for advancing the group of sheets across the top of the stack with the edges remaining in contact with the stack top, an elongated cam surface positioned adjacent said path, a cam follower carried on said advancing means positioned to engage said cam, a linkage between said follower and one of the gripping jaws to move it to gripping position when said cam follower rides on said cam with movement of the advancing means, spring means urging said one gripping jaw to released position, and a release cam positioned along said path and located to be engaged by said cam follower whereby the follower will be cammed off said jaw operating cam whereby the spring will separate said one jaw from the other to release the group of sheets at a predetermined location along said path.

3. A mechanism for removing a group of sheets of relatively soft paper from a vertical stack and keeping the group in aligned relationship comprising, elevating means for elevating the stack of sheets to remove successive groups of sheets from the top of the stack, means for separating the group from the top of the stack including lifting means having a thin leading edge for insertion into the stack and elevating the central portion of the group, said lifting means being narrow to engage only a small portion of the edge of the group of sheets so as to raise the center portion without raising the ends, a pair of gripping jaws including a thin lower jaw movable beneath the group and engaging the raised portion, means moving said jaws to gripping engagement with said raised portion to clamp the group without raising the ends of the group off the stack, means supporting the jaws for moving the 10 group longitudinally of the stack while maintaining the lower jaw close to the stack so that the ends of the group will slide on the stack, a support surface in alignment with the top of the stack for receiving the group to he slid thereon, and aligning stops against which the edge of the group engages on said support surface.

4. A mechanism for removing a group of sheets of relatively soft paper from a vertical stack and keeping the group in aligned relationship in accordance with claim 3 wherein said lifting means is pivotally supported on a stationary pivot point and the elevating means moves the stack upwardly relative to the lifting means for each group moved from the stack.

5. A mechanism for removing a group of sheets of relatively soft paper from a vertical stack and keeping the group in aligned relationship comprising, elevating means for elevating the stack of sheets to remove successive groups of sheets from the top of the stack, means for separating the group from the top of the stack including lifting means having a thin leading edge for insertion into the stack and elevating the central portion of the group, said lifting means being narrow to engage only a small portion of the edge of the group of sheets so as to raise the center portion without raising the ends, a pair of gripping jaws including a thin lower jaw movable beneath the group and engaging the raised portion, means moving said jaws to gripping engagement with said raised portion to clamp the group without raising the ends of the group off the stack, means supporting the jaws for moving the group longitudinally of the stack while maintaining the lower jaw close to the stack so that the ends of the group will slide on the stack, a support surface in alignment with the top of the stack for receiving the group to he slid thereon, and aligning stops against which the edge of the group engages on said support surface, said stop being movable from a stopping position for being engaged by the group on said support member to a retracted position out of the path of travel of the group so that the group can be slid past the stop on said surface.

References Cited in the file of this patent UNITED STATES PATENTS 1,164,802 Freeman May 1, 1913 1,191,966 Harrold July 25, 1916 1,587,855 Redding June 8, 1926 1,847,812 Bur-ton Mar. 1, 1932 1,976,834 Carland :Oct. 16, 1934 1,977,369 Ackley Oct. 16, 1934 2,424,187 Pearce July 15, 1947 2,622,876 Schefe Dec. 23, 1952 2,641,321 Cruzan June 9, 1953 2,658,752 Matteson Nov. 10, 1953 2,688,414 Haas Sept. 7, 1954 2,795,274 Beaulieu June 11, 1957 2,850,090 Biel et al. Sept. 2, 1958 2,988,236 Shields June 13, 1961 FOREIGN PATENTS 1,013,156 Germany Aug. 1, 1957 

1. A MECHANISM FOR REMOVING A SHEAF OF SHEETS FROM A SUPPLY STACK AND ADVANCING THE SHEAF IN ALIGNED RELATIONSHIP COMPRISING A DEVICE FOR SEPARATING A SHEAF OF SHEETS FROM THE TOP OF A SUPPLY STACK BY SLIGHTLY ELEVATING THE CENTER OF THE SHEAF WITH THE EDGES REMAINING IN CONTACT WITH THE STACK, GRIPPING JAWS FOR MOVING AGAINST OPPOSING SURFACES OF SAID SHEAF AT SAID ELEVATED CENTER, THE UPPER OF SAID JAWS HAVING A SOFT RESILIENT SURFACE AND THE LOWER OF SAID JAWS HAVING AN ARCUATE FACE CURVING TO CONFORM TO THE SHEAF OF SHEETS DRAPING DOWNWARDLY AT THE EDGES, MEANS FOR MOVING THE JAWS TOGETHER TO GRIPPING ENGAGEMENT WITH SAID SHEAF, AND ADVANCING MEANS CARRYING SAID JAWS HORIZONTALLY FOR SLIDING THE SHEAF OFF OF THE TOP OF THE STACK. 